This invention relates to hydrostatic transmissions in general and in particular to such transmissions used in applications known as zero turn (“ZT”) vehicles, where the transmission has two independent outputs that can drive the vehicle wheels in opposite directions.
One known ZT design incorporates two separate hydrostatic transmissions and two separate gear and axle housings; with each transmission bolted to a separate housing. A design of this type is shown in U.S. Pat. No. 5,078,222. While such designs offer flexibility, the use of two separate HSTs increases the costs and complexity of the unit.
Other known designs incorporate the hydrostatic transmission and the two output axles into a single housing. Such designs lack the necessary flexibility required to adapt the transaxle unit to a variety of vehicle applications.